Climate Change Lawsuit Against Oil Companies Clears Legal Hurdle, Signals New Era of Accountability

by Nicole Jefferson and Rrita Osmani

First-of-its-kind wrongful death suit filed against ExxonMobil, BP, and Chevron, and other oil companies for their involvement in climate change

The 2021 Pacific Northwest heat dome was a period of extreme heat that saw temperatures averaging around 121.3 F across British Columbia, Oregon, and Washington state and resulted in an estimated 1,400 deaths, making it the hottest and deadliest heatwave that the Pacific Northwest has ever experienced. A civil lawsuit filed on May 29, 2025 in King County Superior Court by the daughter of a woman who died in her car during the extreme heat event is the first-of-its-kind to hold oil companies responsible for their role in exacerbating climate disasters.

In June 2021, 65-year-old Julie Leon was found dead in her car after the internal temperature rose to 110 degrees Fahrenheit. The medical examiner ruled the cause of death was hyperthermia. In the state of Washington, where the suit was filed, more than 400 people died from heat-related causes during the heat dome event.

While Miller Shah LLP is not involved in this case, it signals a growing judicial willingness to consider large-scale environmental and consumer fraud claims—areas central to our firm’s work across environmental litigation, ESG misrepresentation, public fiduciary duty, and false advertising under the False Claims Act. Miller Shah’s environmental whistleblower work similarly seeks to uncover harmful activity that negatively affects public health and the environment.

Complaint Allegations

The complaint names ExxonMobil, BP, Olympic Pipe Line Co., Chevron, Shell, ConocoPhillips, Phillips 66 and alleges that Defendants knew their fossil fuel products would directly impact the environment and understand the potential risks their products posed including atmospheric changes that would result in more destructive weather events and predictable loss of human life. The complaint also argues that these companies hid, downplayed, and misrepresented the risks caused by burning oil and gas. This suit suggests increased scrutiny over oil companies and emphasizes oil companies’ decades-long public propaganda to minimize the effects of fossil fuels. Defendants have not filed a response.

The complaint cites scientists who determined that the catastrophic heat event would have been “virtually impossible” without human contribution to climate change. It also references decades of behavior in which ExxonMobil questions the validity of climate science and their failure to adequately warn about risks of fossil fuels. Misti Leon is seeking the oil companies pay damages in amounts that would be later determined at trial. She is also attempting to require the named oil companies to organize a public education campaign to correct decades of their misinformation.

Mixed Judicial Responses to Climate Change Lawsuits In State Court

Fossil fuel companies have experienced an increase in suits filed against them for promoting misleading information and knowingly causing harm. These suits primarily focus more broadly on oil and gas companies’ harm to infrastructure, property, and public health more generally. The plaintiff is typically a county, city, or state suing the gas or oil company, whereas this Washington state wrongful death suit is being brought by an individual. The Washington state case may establish a precedent for corporate accountability with regard to human deaths.

Climate-related lawsuits have varying success, with some courts more open to cases than others. On May 16, 2025, just two weeks before Leon filed her suit in Washington state, a Pennsylvania judge in Bucks County dismissed a lawsuit against Chevron, BP, Shell, ConocoPhillips, ExxonMobil, Phillips 66, and a petroleum industry trade group that would have forced these companies to pay to fix bridges and install stormwater management projects to address the more frequent and more severe flooding in the area. The order from Judge Corr explained that the claims were not judiciable. Corr held that the claims lacked subject matter jurisdiction. This legal doctrine is becoming increasingly relied upon by state courts to dismiss claims.

In some cases, climate tort litigation was allowed to progress. In Boulder, a climate tort litigation claim against ExxonMobil and Suncor seeking relief for climate change harms proceeded in state court. The City of Boulder asserted claims of unjust enrichment and civil conspiracy among other claims relating to defendants’ production, promotion, and sale of fossil fuels in exacerbating climate change, causing damage to Boulder’s residents and property.

Colorado Supreme Court Justice Richard Gabriel issued an opinion May 12, 2025, stating that the claims are not preempted by federal law, allowing the case to proceed with discovery. This signifies only the second state supreme court decision to allow climate tort litigation to proceed. In 2020, the City and County of Honolulu filed a lawsuit against Sunoco LP and other major oil and gas companies alleging they failed to adequately warn residents of fossil fuel harm and sought financial damages for the infrastructure changes that would be required to adapt to climate change.

A 2023 decision from the Hawaii Supreme Court ruled that the claims are not preempted by federal law. This ruling strayed from precedent that had previously blocked these types of claims from advancing and addressed questions of federal preemption.

These lawsuits raise the issue of corporate liability. They also highlight the necessity for the legal field to predict future needs with rapidly changing environments spurred by climate change and their resulting legal implications. While Leon’s wrongful death suit has yet to be determined, it is seen as a step in the right direction for climate advocacy groups and making visible corporate climate accountability.